Sycamore Seedlings: How to Get Rid of Them

Sycamore seedlings are easy to get rid of if you catch them young. Hoe or pull them in spring while they only have two long seed leaves. Leave them a few weeks and the root goes down deep, snaps when you pull, and the plant comes back.

This guide covers spotting them, clearing the spring flush, dealing with lawns, gravel and gutters, removing woody saplings, and keeping horses safe.

Why do I get so many sycamore seedlings?

There is almost certainly a mature sycamore (Acer pseudoplatanus) nearby. It isn’t a native tree, but it has spread right across Britain. Each tree drops huge numbers of winged seeds in autumn.

Those paired seeds are the spinning “helicopters” children love to throw. The wings carry them a good way on the wind, so a neighbour’s tree can seed your garden too. They land in borders, gravel, lawns and gutters, sit through winter, then come up in spring.

Every helicopter carries a pair of seeds. A handful like this in autumn means a carpet of seedlings next spring.

When do sycamore seedlings come up?

Seedlings appear in March and April. Here’s how the year goes:

1. Autumn: the seeds fall from September to November.
2. Winter: they need a cold, damp spell before they will grow.
3. Spring: two long, narrow seed leaves appear. They look nothing like a maple leaf.
4. Late spring: the first five-lobed, maple-shaped leaf opens.
5. Early summer: the root is already deep and the stem starts to toughen.

The common mistake is waiting until they look like proper little trees. By then the root has gone down, so pulling snaps the top off and the root regrows. Get them while they still have just the two seed leaves.

This is the moment to hoe: two long seed leaves with the first maple-shaped leaf just opening.

How to tell sycamore seedlings from ash and field maple

Check before you pull. Field maple is a native tree that is good for wildlife, so you may want to keep one in a hedge.

• Sycamore has a large leaf with five pointed, toothed lobes. The leaf stalk is often reddish.
• Field maple (Acer campestre) has smaller leaves with rounded, blunt lobes.
• Norway maple has sharper lobes ending in fine points.
• Ash looks completely different. Each leaf is made of several pairs of narrow leaflets along a stalk.

At the seed-leaf stage the maples all look alike. If you’re unsure, wait for the first true leaf before deciding. Take care with ornamental maples too: the Japanese maple care guide shows the ones you’d never want to pull by mistake.

Left to right: the big five-lobed sycamore leaf, the smaller field maple leaf and an ash leaf made of paired leaflets.

Which removal method should you use?

It depends on how old the seedling is. Hoeing young seedlings is quick and free. Cutting woody ones on its own is the worst option, because sycamore regrows from the stump.

Hoeing and pulling the spring flush

A hoe is the fastest tool for a carpet of seedlings. Work on a dry, breezy morning, so the cut seedlings shrivel instead of rooting back into damp soil. A Dutch or oscillating hoe slices just below the surface and clears a border in minutes. The hoeing borders guide covers the technique and which hoe to choose.

Hand-pulling suits gravel, pots and tight corners. Pull when the soil is moist so the whole root comes up. On dry ground the stem snaps and the root stays behind.

Clear them between March and May, and go over the ground again every two or three weeks as more appear. You don’t need any weedkiller for young seedlings.

Hoeing a gravel drive on a dry morning. Young seedlings lift out easily before they root into the base below the stones.

Clearing seedlings from lawns, gravel and gutters

Each surface needs a slightly different approach.

Lawns: just keep mowing. Sycamore seedlings can’t survive having their tops cut off again and again, so they die out within a season.

Gravel drives and paths: hoe or pull them before the roots reach the layer under the stones. Once rooted in, they need digging out. A weed membrane under gravel stops most seedlings taking hold.

Gutters and downpipes: seedlings grow happily in the leaf litter that collects there, and their roots can block downpipes. Clear gutters each autumn and again in spring.

Seedlings scattered through a lawn like this disappear with normal mowing, so there’s no need to weed them by hand.

How to get rid of woody sycamore saplings

Once a seedling is a year or more old and as thick as a pencil, pulling won’t work. You have two options.

Dig it out. Fork out the whole root, including the swollen base of the stem. Any piece of root left behind can regrow. On heavy clay this gets hard work fast, which is another reason to catch them young.

Cut and treat the stump. For a thick sapling you can’t dig, saw it off low. Straight away, treat the fresh cut with a stump killer approved for garden use. Follow the label for how to apply it and the best time of year. This stops the stump sprouting a thicket of new shoots.

Save stump killer for saplings too woody to pull. Young seedlings are quicker to hoe.

Treat a freshly sawn stump straight away with an approved stump killer, or it will sprout new shoots.

How to stop sycamore seedlings coming back

Clearing seedlings each spring deals with the symptom. Two things cut the numbers for good.

Cover bare soil. A mulch of bark, compost or leaf mould 7-10cm deep over cleared borders in late winter stops many seeds coming up. A layer of cardboard under mulch works well on bigger areas, as the cardboard mulch guide explains.

Fewer seeds landing. If the tree is yours and you don’t want it, removing it ends the seed rain. Check with your council first if it may have a Tree Preservation Order or you’re in a conservation area. If the tree is a neighbour’s, you’ll be clearing seedlings each year, so mulch and hoe.

Gardener’s tip: Hoe on a dry, breezy morning, never just after rain. Cut seedlings left on damp soil can root again. On a dry day they wilt quickly and can stay where they fall.

Sycamore and horses: atypical myopathy

If you keep horses, this matters. Sycamore seeds and seedlings contain a toxin that can cause atypical myopathy in horses. It is a serious muscle disease and is often fatal.

The risk is highest in autumn, when the seeds fall, and spring, when seedlings come up. Horses on short, bare grazing near a sycamore are most at risk, because they eat things they would normally leave.

Warning: Fence horses away from sycamore seeds and seedlings, clear them from grazing, and give extra hay when grass is short. Signs include stiffness, weakness, dark urine and reluctance to move. Call a vet straight away if you’re worried.

Clearing seedlings along a paddock fence keeps them out of reach of grazing horses in spring and autumn.

Is a sycamore tree ever worth keeping?

Yes, in the right place. A sycamore copes with wind, salt and pollution better than most trees, so it makes a tough windbreak on exposed or coastal sites. It supports plenty of insects, which in turn feed birds.

The trouble is how freely it seeds. If you keep one, make sure it is well away from horses and small borders. Sycamores often get black blotches on their leaves in late summer; the tar spot guide explains why that’s nothing to worry about. Crispy brown leaf edges are a different problem, covered in the acer leaf scorch guide.

Common mistakes with sycamore seedlings

• Waiting until they look like trees. By then the root is deep. Hoe at the two-seed-leaf stage.
• Cutting saplings and hoping. Sycamore regrows from a cut stump. Dig out the root or treat the stump.
• Pulling from dry soil. The stem snaps and the root stays. Pull when the soil is moist.
• Leaving seedlings in horse grazing. Clear them from paddocks in spring and autumn.
• Forgetting the gutters. Seedlings root in gutter debris and block downpipes.

Sycamore seedling calendar

Frequently asked questions

How do you get rid of sycamore seedlings?

Hoe or hand-pull them at the two-leaf stage, before the root goes deep. Mow seedlings in lawns, dig out woody saplings whole, and use an approved stump killer on thick ones you can’t dig. A deep mulch stops many new ones coming up.

Why do I have so many sycamore seedlings?

There is almost certainly a mature sycamore nearby. Each tree drops huge numbers of winged seeds in autumn, and the wind carries them across gardens. Most come up the following spring.

Will sycamore seedlings grow back if I cut them?

Yes, once they are woody they regrow from the stump. Cutting or strimming only knocks them back. Dig out the whole root, or cut low and treat the fresh stump with an approved stump killer.

Are sycamore seedlings poisonous to horses?

Yes, the seeds and seedlings can cause a serious, often fatal, muscle disease. It is called atypical myopathy. Keep horses away from fallen seeds and seedlings, and call a vet straight away if you suspect it.

How do you tell a sycamore seedling from ash or field maple?

Sycamore has a large five-lobed leaf with toothed edges. Ash has leaves made of several pairs of leaflets. Field maple has smaller leaves with rounded lobes. At the seed-leaf stage maples look alike, so wait for the first true leaf.

Does mowing get rid of sycamore seedlings?

Yes, regular mowing kills them in a lawn. They can’t cope with having their tops cut off again and again. Keep mowing as normal from spring.

What kills sycamore saplings for good?

Digging out the whole root, or treating the cut stump. Any root left in the ground can regrow. For a thick sapling, saw it low and treat the fresh cut with an approved stump killer, following the label.

When is the best time to remove sycamore seedlings?

March to May, while they only have their two seed leaves. That’s when they come out easily. Older, woody saplings can be dug out whenever the soil is workable.

For other unwanted plants, the common garden weeds guide and the problems hub can help. To keep borders clear year after year, read our guide on how to prevent weeds without chemicals.